1. Field of Invention
The present invention relates to certain 3-(pyrrol-2-ylmethylidene)-2-indolinone derivatives that are prodrugs of compounds that modulate the activity of protein kinases (“PKs”). Pharmaceutical compositions comprising these compounds, methods of treating diseases related to abnormal PK activity utilizing pharmaceutical compositions comprising these compounds and methods of preparing them are also disclosed.
2. State of the Art
The following is offered as background information only and is not admitted to be prior art to the present invention.
PKs are enzymes that catalyze the phosphorylation of hydroxy groups on tyrosine, serine and threonine residues of proteins. The consequences of this seemingly simple activity are staggering; cell growth, differentiation and proliferation, i.e., virtually all aspects of cell life in one way or another depend on PK activity. Furthermore, abnormal PK activity has been related to a host of disorders, ranging from relatively non life threatening diseases such as psoriasis to extremely virulent diseases such as glioblastoma (brain cancer) (see U.S. Pat. No. 5,792,783 which is incorporated herein by reference in its entirety).
In view of the apparent link between PK-related cellular activities and wide variety of human disorders, it is no surprise that a great deal of effort is being expended in an attempt to identify ways to modulate PK activity. Some of this effort has involved biomimetic approaches using large molecules patterned on those involved in the actual cellular processes (e.g., mutant ligands (U.S. Pat. No. 4,966,849); soluble receptors and antibodies (Published PCT Appl. WO 94/10202, Kendall and Thomas, Proc. Nat'l Acad. Sci., 90:10705–09 (1994), Kim, et al., Nature, 362:841–844 (1993)); RNA ligands (Jelinek, et al., Biochemistry, 33:10450–56); Takano, et al., Mol. Bio. Cell 4:358A (1993); Kinsella, et al., Exp. Cell Res. 199:56–62 (1992); Wright, et al., J. Cellular Phys., 152:448–57) and tyrosine kinase inhibitors (Published PCT Appls. WO 94/03427; WO 92/21660; WO 91/15495; WO 94/14808; U.S. Pat. No. 5,330,992; Mariani, et al., Proc. Am. Assoc. Cancer Res., 35:2268 (1994)).
In addition to the above, attempts have been made to identify small molecules which act as PK inhibitors. For example, bis-monocylic, bicyclic and heterocyclic aryl compounds (Published PCT Appl. WO 92/20642), vinyleneazaindole derivatives (Published PCT Appl. WO 94/14808) and 1-cyclopropyl-4-pyridylquinolones (U.S. Pat. No. 5,330,992) have been described as tyrosine kinase inhibitors. Styryl compounds (U.S. Pat. No. 5,217,999), styryl-substituted pyridyl compounds (U.S. Pat. No. 5,302,606), quinazoline derivatives (EP App. No.0 566 266 A1), selenaindoles and selenides (Published PCT Appl. WO 94/03427), tricyclic polyhydroxylic compounds (Published PCT Appl. WO 92/21660), benzylphosphonic acid compounds (Published PCT Appl. WO 91/15495) and indolinone compounds (U.S. Pat. No. 5,792,783) have all been described as PTK inhibitors useful in the treatment of cancer. However these compounds have limited utility because of toxicity or poor bioavailability. Accordingly, there is a need for compounds that overcome these limitations. The compounds of the present invention fulfil this need.